As society has grown more complex, an increasing need has arisen for more and better protection devices that can, and will, warn of unwanted and/or hazardous conditions. One of the more potentially dangerous of these conditions can arise when a fire is ignited that is not readily detected. Obviously, such a fire can cause serious, and possibly fatal, injury to human and/or other animal life, as well as causing extensive property damage, particularly if not detected early and quickly brought under control. But such a fire might not be readily detected by observation, either by igniting in an area not then frequented by a human observer, or due to inability of observation, such as during periods of sleep.
Detection devices have been heretofore suggested and/or utilized for indicating the presence of conditions such as fire, and while these devices have heretofore been utilized with varying degrees of success, a need has still existed for a device capable of independent operation that provides reliable monitoring to sense the presence of fire even though such monitoring extends over long periods of time.
Among devices now known and utilized for fire detection are systems that utilize external voltage sources, such as, for example, systems described and claimed in U.S. Pat. application Ser. No. 314,689, filed Dec. 13, 1972 by Ronn H. Mayer and entitled "Ionization Detector Apparatus," and U.S. Pat. application Ser. No. 504,489, filed Sept. 9, 1974 by William Webb, Jr., and entitled "Combustion Detection Device," both of which applications are assigned to the assignee of the present invention.